You can configure Afaria to use the same relay server as Unwired Server, even if the Afaria Server is installed on a seperate host computer than the Unwired Server tier.
This configuration, which Sybase recommends, lets you seperate the servers, but still share the same relay server installation. Afaria can then also use the same data tier used by Unwired Server.
Each server can be a member of only one cluster. For high availability, there must be at least two servers defined for a cluster.